Discussion

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Figure 2: The patient’s repeat ECG demonstrated ST elevation in V1–V3 with reciprocal ST depression in II and aVF.
Images: Youstina Michael

An isolated TWI in aVL is not a well-recognized early sign of occlusion across the relevant medical specialties. In a survey by Hassen et al, only 25 percent of physicians identified an isolated TWI in aVL as abnormal, although emergency physicians were better than other specialties at recognition.³ This study demonstrated that angiograms done specifically during the evaluation for STEMI revealed mid-LAD lesion association with TWI with a sensitivity of nearly 88 percent, and positive predictive value (PPV) of 81 percent for mid-LAD lesions greater than 50 percent. Patients with similar ECG findings who underwent coronary angiography for other reasons demonstrated a sensitivity of 65 percent, PPV of 83 percent, and specificity of 67 percent for mid-LAD lesions 70 percent or greater. The LAD supplies a large portion of the heart and renders a large area of myocardium at risk in the setting of an occlusion, making this subtle ECG change important to identify.

For hospitals that do not have an on-site catheterization lab, thrombolytics may be required as a bridge to definitive therapy. (“Time is myocardium.”) Patients who receive thrombolytic therapy may have improvement in chest pain and ECG findings. However, these patients require cardiac catheterization within 24 hours of presentation. Early recognition and treatment of patients with concerning presentations and an isolated TWI in aVL may save a life.

Dr. Michael is an attending physician, Dr. Sokup is a resident, and Dr. Jeong is residency director and associate chair for education in the department of emergency medicine at Coney Island Hospital in Brooklyn, New York.

References

1. Okada M, Yotsukura M, Shimada T, et al. Clinical implications of isolated T wave inversion in adults: electrocardiographic differentiation of the underlying causes of this phenomenon. J Am Coll Cardiol. 1994;24(3):739-745.
2. Farhan HL, Hassan KS, Al-Belushi A, et al. Diagnostic value of electrocardiographic T wave inversion in lead aVL in diagnosing coronary artery disease in patients with chronic stable angina. Oman Med J. 2010;25(2):124-127.
3. Hassen GW, Costea A, Carrazco C, et al. Isolated T wave inversion in lead aVL: an ECG survey and a case report. Emerg Med Int. 2015;2015:250614.